Combined coal dust and gas firing system



June 15, 1965 o. ANSCHUTZ 3,188,987

commas GOAL nusw AND GAS FIRING SYSTEM Filed March 22. 1962 I5 Sheets-Sheet l June 15, 1965 -o. ANSCHUTZ COMBINED GOAL DUST AND GAS FIRING SYSTEM Filed March 22. 1962 S Sheets-Sheet 2 q l n M nl ouu o u a a n n n I o o u u o a u o n o o n u o I a o o a n o Q a a u o I I O 6 If]! 5 L u 1 0? h Q I a". n u "v 1 m 1'. I "II 0 I P I, I o i i n 1 n 4 a a k 1 WWWWMWI W n/r01? h u 7 M y M W June 15, 1965 o. ANSCHUTZ comammn COAL DUST AND GAS FIRING SYSTEM Filed March 22, 1962 5 Sheets-Sheet 3 United States Patent 3,188,987 COMBINED COAL DUST AND GAS FIRING SYSTEM Otto Anschutz, Gummersbach, Rhinelaud, Germany,

assignor to L. & C. Steinmiiller G.m.b.H., Gunimersbach, Rhineland, Germany Filed Mar. 22, 1962, Ser. No. 181,697 Claims priority, application Germany, Mar. 25, 1961,

r a St 17,628

6 Claims. (Cl. 110-22) The present invention relates to coal dust firing systems, and, particularly to firing systems of the stepped type. The heating value of the fuel fired in these firing systems varies considerably, particularly when low-grade bituminous coal is involved,

Inasmuch as for reasons of economy, the firing system has to be designed for a median heating value, conditions can easily occur which, at full load, make it impossible to hold the load. The addition of gas burners frequently fails because the inert gases which develop with the shorter coal dust flames impede the complete combustion of the gases. This isgparticularly true with all firing systems in which gas flames come into contact with flue gases.

When the gas burners are arranged in an ordinary combustion chamber, there will additionally exist the danger that when being turned off, they are not protected against absorption of radiant heat (Einstrahlung), and when arranged in the side or rear wall, slag.

It is, therefore, an object of the present invention to provide a coal dust firing system, which will overcome the above-mentioned drawbacks.

It is another object of this invention to provide a coal dust firing system in which the combustion of the flue gases of the gas firing system will not be afiected by the inert gases. 7

These and other objects and advantages of the invention will appear more clearly from the following specification in connection with the accompanying drawing diagrammatically illustrating a stepped firing system. The invention, which concerns a melting chamber firing system (Schmelzkammerfeuerung) comprising a combustion chamber and, if desired, a post-combustion chamber and radiation chamber, is characterized in that a gas burner equipped combustion chamber is separated from the radiation chamber while the gas exit of said combustion chamber leads directly into the radiation chamber. More specifically, behind the melting chamber proper, i.e., be hind the slag catching grate, a separate chamber is provided, separated from the radiation chamber and serving as combustion chamber for the gas firing system. When stepped combustion chambers are employed, the said separate chamber joins, as additional step, the main combustion chamber. The length of said separate chamber depends on the length 'of' the. gas flame which, when leaving the gas combustion'chamber, is supposed to have substantially burned out.

yAn embodiment of the invention is illustrated in the following figures, from which:

FIGURE 1 shows a vertical sectional view of a melt- 7 ing chamber firing system with three combustion chambers arranged in a stepped position and a radiation chamb plane II-II of FIGURE '1,

FIGURE 3 shows a detail of the slag catching grate in enlarged scale, 1

FIGURE 2 shows a horizontal sectional view on line' FIGURE 6 shows a vertical sectional view of a gas burner combined with an oil burner.

3,188,987 Patented June 15, 1965 Referring now to the drawing in detail, which illusstrates an embodiment of the invention in connection with a stepped firing system, the firing system comprises a main combustion chamber 1 equipped with burners 11, and furthermore comprises a combustion chamber portion 2 extending to form a horizonal chamber portion at the bottom of main chamber '1, and equipped with coal dust burners 12. The stepped firing system also comprises a gas burner chamber 3 with gas burners 13. As FIG. 2 shows the gas burner chamber 3 extends over the entire width of the fire chamber and joins the stepped combustion chamber portions 1, 2 as an upper additional step. Similar to the burners of the stepped firing system, the gas burners 13 are arranged in the ceiling of the gas burner chamber 3 so that the gas burner chamber is passed through by the combustion gases in the direction from the top toward the bottom. The gas burner chamber has a bottom exit opening 3a which leads into the radiation chamber 5 directly above the slag catching grate 6, which latter forms the dividing line between the combustion chamber 2 and the radiation chamber 5. In this way, the temperture of the combustion gases leaving the gas burner chamber 3 corresponds approximately to the temperature of the flue gases at said point, which line gases originated in the stepped combustion chamber. The bottom portion of the firing system is provided with a slag discharge opening 4. As to be seen from FIGS. 3 and 4 the slag catching grate is formed by pipes which merge on the inside with wall 7, separating the main combustion chamber 1 from the gas burner chamber 3 and from the radiation chamber 5. The partition between the gas burner chamber 3 and the radiation chamber 5 is "ice designated with the reference numeral 8.

a layer on the side of chamber 3, while the other side isbare. A combined gas and oil burner 13 is illustrated in FIG. 6. Here the oil nozzle is designated with numeral 14. 15 is the inner tube for core air, 16 the gas channel and 17 the channel for second air. In this way oil and gas may be burned separately or together.

When the firing system according to the invention is in operation, the burners 11 and 12 are turned on in the manner known per se while, when only a slight load is involved, a portion of the burner 11 or all burners 11 may be turned off and only burners 12 are in operation. If, however, the firing system is operated at full load, and if it should occur that the full load cannot be maintained by means of the burners 11 and 12 because of the poorer heating value of the coal being fired at said time, additionally, the burners 13 will be turned on. It is, of course, also possible when operating the firing system below full load, to distribute the load at random over the burners 11, 12 and 13.

When the burners 13 are turned off, a portion of the flue gases passing through the slag catching grate will also flow into the gas burner chamber 3. This part of the flue gases will, however, at the time it reaches the ceiling of the gas burner 13 equipped chamber 3, have cooled to such an extent that burning up of the burner 13 will no longer have to be feared.

If all of the burners are in operation, the dust jets entering through burners 11 and 12 will have sufficient time to burn out until they pass through the slag catching grate 6 and pass into the radiation chamber 5. Similarly, the gas flames of the burners 13 will have burned out completely when they pass from the lower end of the combustion chamber 3 into the radiation chamber 5 and combine with the flue gases from the combustion chambers 1 and 2. Thus, a mutual interference of the commay-be covered at chamber 3, 1

bustion by the flue gases of hers, will be practically mpossible. v

The wall 8,;similar to the other wall portions'of the radiationchamber 5, cfo'nsis't's of evaporatori ipes and As will be evident om tion yields a' numberofimportant advantages? (a) 'With melting chamber boilers (Schmelzkammerkesselnfthere isobtairled the'possibility to maintain "great portion of the load by the, gas firing system outside the melting chamber, whichfact is of particular impor- (b) The distribution of the V a over the various combustion chambers.

(c) The fuel gases of the" gas firing system engage the coal :dust flue gases only when. both have burned out, whereby a mutual interference of the gases, will beiexcluded. 7

that. side which 'iaces the c' omb'ustion' combustionby inert (d) The flue gases leaving thegas' burner chamber will,

the various combustion ch'am-.

a v Q 4 burner means therein said discharge opening at the bottomrof said gas fired cembustion chamber, leading 2 directly intoj'said radiation chamber at the bottom thereof theabove,thelpresent'i v 7 than said coaldust fired chamber.

when meeting'the coal idust flue gases leaving he P I v i said vertical chamber portiomiand said lower horizontal combustion chamber, have approximately} the same temperature as said last-mentioned gases whereby theformag tion of banks in the radiation chamber andon the post-l V heating surfaceiwillbeavoidedl 1 2 s i (e) The gasburners are located so'thatjthey areabsolutely protected against theabsorption of heat 'by radia tion, and also against slagging.

(f) The. shifting from one fuel type to another can be larly, any-desired distribution 'ofthe load may beadjus't'ed for co'ialdust gas burner operation.

- (g) The-intermediate oven-heating can betterfbe held.

within properlirnits than is possible when the gas is blown directly into the melting chamber. 5 a

The over-heating'caneasily be controlled. a

"It is, f course, to -be understoodthat thepresent in-j;

vention is, by ,no, means, limited to the particular conestruction shown in the drawing, but also comprises any modifications within the scope of the appended claims.

7 What I claim is: j

11A melting chamber firing 'systemwhich comprises:

means defining a substantially vertical steppedl'coal dust chamber portion connected at oneend to'the. bottom of said coal dust fired combustion chamber'and extending 0 eifected during the operation of the firing system} Simi:

ias"

therefrom in the flow. direction of 'the fiue gases, means defining a radiation chamber connected to and extending upwardly from, the other; 'end of said horizontal chamber portion, a' slag 'collecting grate-arranged between said other "endof said horizontal chamber portion and said radiation chamber through which said'flue gases pass,- a

slag dischargeop'ening in the-bottom of said horizontal chamber portion which is arranged ahead of the slag collecting grate in the flow direction ofthe'fiu'e gases,- and means defining a substantially vertical gas fired combustion chamber separate from both said firstvertical combustion chamber and said 'radiation chamber and located therebetween and having a discharge opening at. the bottom thereof, said lastnarned means comprising subfi stantially vertical partitions separating said gas fired combustion chamber from said coal dust' fired combustion" chamber and separating said gas'fired combustion icha'r'na ber from said radiation chamber, and a ceiling havinggas her portion? r 2. The arrangement according totclaim l wherein said gas' fired combustion-chamber extends to a higher level on'theside of said grate opposite saidhorizontal chamcross-sectional;areaofijsaid first portionof said substang tially vertical combustionchamber isf smaller -at,the

bottom thereof than at the top f ,1) v v 1 a g 5.{ A melting fchambe'ri firing system which comprises :2 wall rneansjdefining a coal dust fired combustion chamber in'the'rforrn of a substantiallyfL shaped chamberwith an upper jvertical and alo'wer horizontal portion,'a step inone w all j of .said vertical portion providing, ceiling por 'tions,; each ceiling .portibn being providedwith, coal dust burners a'rranged to fire in the direction qf the. bottom of portion connecting at one end to the bottom of said verticalrch amber 'portion' and,exten'dingtherefrom inv the flow direction of the flue gases, -meansdefining*a radiation chamber connected to and extending upwardlyfrom the other end of. said horizontal chamber portion, a slagcoh lectin'g grate .arranged'jbetween said other end' of said horizontal chamber portion, and isaid radiation chamber through which said flue gases passQand means defining substantiallyverticalgasfiredcombustion chamber separatefrom said Lfsha'ped chamber ,andisaid. radiation chambe'rand located therebetjwe'en and havinga discharge opening atrthe; bottom thereof,,-saidlast named rneanscomprising substantially verticalpartitions-separating said gas r'fired combustion chamberifrom said'coal dust firedcom- -'bustion chamber and separating said gas fired combustion chamber .from said radiation chamber, and a-ceiling having gas lburnerrmeanstherein,saidldischarge opening at the bottom of'said gi ls ,fired combustion chamber, leading directlyinto said radiationchamber atthe bottom thereof on the side of said grate opposite said horizontal chamber portion, the' ceilingl'of said gasfired combustion chamber being located ata'higherlevel than tha t'of said coal dust fired combustion chamber. 3 I

6. The arrangementQaccording"tor claim 5 which ,in-'

cludes oil burner means in; the. ceiling of said last named bombustionichamberj I 1 f References Cited by the-Examiner a UNITED sraires rnrnnrs 1,665,344 4/28, 1,872,138 8/32 I 122-235 1,938,335 12/33. 110- 22X 2,033,685: 3 36 ,'122-235 2,206,265 7/40,. sa thqfinl fl1-22, 235 2,231,782 2/41. Bailey-et al. 122-235 2,245,209 I 6/4,l .-,;"May o' 122 235 2,330,240 9/43 'Raynor;; 122-235 Qf'FOREIGNfPATENTS 852,965 11/60 "Great Britain.

JAMES W! WESTHAVER; Mariam-a1 E R EDIE R1 M TIESON, Jra. CHARLES SUKALO, Examiners} UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,188,987 June 15, 1965 Otto Anschiitz It is hereby certified that error appears in the above numbered patent reqiiring correction and that the said Letters Patent should read as correctedbelow.

In the grant, line 1, and in the heading to the printed o Anschutz", each occurrence,

specification, line 4, for "Ott in the heading to the drawings,

read Otto Anschiitz Sheets l to 3, for "O. ANSCHUTZ", each occurrence, read O. ANSCFIUTZ Signed and sealed this 7th day of December 1965.,

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Allcsting Officer Commissioner of Patents 

1. A MELTING CHAMBER FIRING SYSTEM WHICH COMPRISES: MEANS DEFINING A SUBSTANTIALLY VERTICAL STEPPED COAL DUST FIRED COMBUSTION CHAMBER COMPRISING FIRST AND SECOND PORTIONS EACH HAVING A CEILING AND EACH HAVING COAL DUST BURNER MEANS IN THE CEILING THEREOF AND EACH BEING PASSED THROUGH BY THE FLUE GASES FROM THE TOP TO THE BOTTOM, AND MEANS DEFINING A SUBSTANTIALLY HORIZONTAL COMBUSTION CHAMBER PORTION CONNECTED AT ONE END TO THE BOTTOM OF SAID COAL DUST FIRED COMBUSTION CHAMBER AND EXTENDING THEREFROM IN THE FLOW DIRECTION OF THE FLUE GASES, MEANS DEFINING A RADIATION CHAMBER CONNECTED TO AND EXTENDING UPWARDLY FROM THE OTHER END OF SAID HORIZONTGAL CHAMBER PORTION, A SLAG COLLECTING GRATE ARRANGED BETWEEN SAID OTHER END OF SAID HORIZONTAL CHAMBER PORTION AND SAID RADIATION CHAMBER THROUGH WHICH SAID FLUE GASES PASS, A SLAG DISCHARGE OPENING IN THE BOTTOM OF SAID HORIZONTAL CHAMBER PORTION WHICH IS ARRANGED AHEAD OF THE SLAG COLLECTING GRATE IN THE FLOW DIRECTION OF THE FLUE GASES, AND MEANS DEFINING A SUBSTANTIALLY VERTICAL GAS FIRED COMBUSTION CHAMBER SEPARATE FROM BOTH SAID FIRST VERTICAL COMBUSTION CHAMBER AND SAID RADIATION CHAMBER AND LOCATED THEREBETWEEN AND HAVING A DISCHARGE OPENING AT THE BOTTOM THEREOF, SAID LAST NAMED MEANS COMPRISING SUBSTANTIALLY VERTICAL PARTITIONS SEPARATING SAID GAS FIRED COMBUSTION CHAMBER FROM SAID COAL DUST FIRED COMBUSTION CHAMBER AND SEPARATING SAID GAS FIRED COMBUSTION CHAMBER FROM SAID RADIATION CHAMBER, AND A CEILING HAVING GAS BURNER MEANS THEREIN, SAID DISCHARGE OPENING AT THE BOTTOM OF SAID GAS FIRED COMBUSTION CHAMBER LEADING DIRECTLY INTO SAID RADIATION CHAMBER AT THE BOTTOM THEREOF ON THE SIDE OF SAID GRATE OPPOSITE SAID HORIZONTAL CHAMBER PORTION. 